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Fix extent_alloc_dss() regression.

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Fix extent_alloc_dss() to account for bytes that are not a multiple of
the page size.  This regression was introduced by
577d4572b0 (Make dss operations
lockless.), which was first released in 4.3.0.
This commit is contained in:
Jason Evans 2017-02-09 13:00:59 -08:00
parent 6b8ef771a9
commit cd2501efd6
1 changed files with 29 additions and 19 deletions
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48
src/extent_dss.c
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@ -121,35 +121,45 @@ extent_alloc_dss(tsdn_t *tsdn, arena_t *arena, void *new_addr, size_t size,
* malloc.
*/
while (true) {
void *ret, *max_cur, *gap_addr, *dss_next, *dss_prev;
size_t gap_size;
intptr_t incr;
max_cur = extent_dss_max_update(new_addr);
void *max_cur = extent_dss_max_update(new_addr);
if (max_cur == NULL) {
goto label_oom;
}
/*
* Compute how much gap space (if any) is necessary to
* satisfy alignment. This space can be recycled for
* later use.
* Compute how much page-aligned gap space (if any) is
* necessary to satisfy alignment. This space can be
* recycled for later use.
*/
gap_addr = (void *)(PAGE_CEILING((uintptr_t)max_cur));
ret = (void *)ALIGNMENT_CEILING((uintptr_t)gap_addr,
PAGE_CEILING(alignment));
gap_size = (uintptr_t)ret - (uintptr_t)gap_addr;
if (gap_size != 0) {
extent_init(gap, arena, gap_addr, gap_size,
gap_size, arena_extent_sn_next(arena),
void *gap_addr_page = (void *)(PAGE_CEILING(
(uintptr_t)max_cur));
void *ret = (void *)ALIGNMENT_CEILING(
(uintptr_t)gap_addr_page, alignment);
size_t gap_size_page = (uintptr_t)ret -
(uintptr_t)gap_addr_page;
if (gap_size_page != 0) {
extent_init(gap, arena, gap_addr_page,
gap_size_page, gap_size_page,
arena_extent_sn_next(arena),
extent_state_active, false, true, false);
}
dss_next = (void *)((uintptr_t)ret + size);
/*
* Compute the address just past the end of the desired
* allocation space.
*/
void *dss_next = (void *)((uintptr_t)ret + size);
if ((uintptr_t)ret < (uintptr_t)max_cur ||
(uintptr_t)dss_next < (uintptr_t)max_cur) {
goto label_oom; /* Wrap-around. */
}
incr = gap_size + size;
/* Compute the increment, including subpage bytes. */
void *gap_addr_subpage = max_cur;
size_t gap_size_subpage = (uintptr_t)ret -
(uintptr_t)gap_addr_subpage;
intptr_t incr = gap_size_subpage + size;
assert((uintptr_t)max_cur + incr == (uintptr_t)ret +
size);
/*
* Optimistically update dss_max, and roll back below if
@ -162,10 +172,10 @@ extent_alloc_dss(tsdn_t *tsdn, arena_t *arena, void *new_addr, size_t size,
}
/* Try to allocate. */
dss_prev = extent_dss_sbrk(incr);
void *dss_prev = extent_dss_sbrk(incr);
if (dss_prev == max_cur) {
/* Success. */
if (gap_size != 0) {
if (gap_size_page != 0) {
extent_dalloc_gap(tsdn, arena, gap);
} else {
extent_dalloc(tsdn, arena, gap);